WO2012046728A1

WO2012046728A1 - Packet transfer apparatus, packet transfer method, and program

Info

Publication number: WO2012046728A1
Application number: PCT/JP2011/072872
Authority: WO
Inventors: 村上　哲也; 聡松嶋
Original assignee: 株式会社Ａｃｃｅｓｓ; ソフトバンクＢｂ株式会社
Priority date: 2010-10-05
Filing date: 2011-10-04
Publication date: 2012-04-12
Also published as: JP2012080465A; JP5608870B2

Abstract

Provided is a packet transfer apparatus that has allotted thereto an IP address that is the same as a different apparatus on the network, and a port range that is different therefrom. The packet transfer apparatus is configured to be provided with: a packet reception unit for receiving a data packet; a packet identification unit for evaluating, on the basis of the destination IP address and destination port number of a data packet received by the packet reception unit, whether the received data packet is destined for the packet transfer apparatus; and a packet transfer unit for transmitting the data packet when the packet identification unit evaluates that the data packet is not destined for the packet transfer apparatus.

Description

Packet transfer apparatus, packet transfer method, and program

The present invention relates to a packet transfer device, a packet transfer method, and a program in an A + P environment.

With the development of the Internet, it is said that the inventory of IPv4 addresses distributed by the Internet registry that manages IP addresses will be reduced and will be depleted in the near future. Therefore, in recent years, IPv6 having an enormous address space has been introduced as a replacement for IPv4, and IPv6-compatible devices, IPv6 content services, and the like have begun to be provided. However, it is expected that all devices and services will be compatible with IPv6, and provision of IPv4 services to existing IPv4 compatible devices will continue for the time being even after IPv4 addresses are exhausted. For this reason, a method such as “IPv4 over IPv4” for using IPv6 and IPv4 in parallel is proposed, and particularly in advanced countries where the IPv4 network is spreading, to delay the exhaustion of IPv4 addresses. Various methods have been developed.

As one of such methods, a method called A + P (Address Plus Port) has recently been proposed by IETF (Internet Engineering Task Forth) and the like. R. Despres, Ed. “Stateless Address Mapping (SAM)-a Simplified Mesh-Softwire Model” draft-despres-sam-01, IETF Internet-Draft, July, 2010 (hereinafter referred to as “Non-Patent Document 1”), R . Bush, Ed. “The A + P Approach to the IPv4 Address Shortage” draft-ymbk-aplusp-05, IETF Internet-Draft, October, 2009 (hereinafter referred to as “Non-Patent Document 2”) and M. Boucadair, Ed ., P. Levis, France Telecom, G. Bajko, T. Savolainen, Nokia “IPv4 Connectivity Access in the Context of IPv4 Address Exhaustion: Port Range based IP Architecture” draft-boucadair-port-range-02.txt, IETF Internet -Draft, July, 2009 (hereinafter referred to as “Non-Patent Document 3”) is an Internet draft that describes technical specifications related to A + P. In A + P, a TCP / UDP port range different from a common IPv4 address is provided from an Internet service provider to a plurality of users on a network (specifically, CPE (Customer Premises Equipment including a user home router) or home gateway). Assigned. In this way, by sharing one IPv4 address among a plurality of users, the number of distributed IPv4 addresses can be reduced, and by limiting the port range to the user, each user can be identified. Yes. In addition, A. Durand et.al, Ed. “Dual-Stack Lite Broadband Deployments Following IPv4 Exhaustion” draft-ietf-softwire-dual-stack-lite-06.txt, IETF Internet-Draft, August , 2010 (hereinafter referred to as “Non-Patent Document 4”), a technique called DS-Lite is also known.

However, in the case where the same IPv4 address is assigned to a plurality of users by A + P, there is a problem that the user's terminals to which the same IPv4 address is assigned cannot communicate appropriately with the conventional packet transfer technology. Specifically, for example, it is assumed that a common IPv4 address and a different port range are assigned to CPE1 installed in the home of user A and CPE2 installed in the home of user B as follows by A + P.
(CPE1)
IPv4 address: 120.10.10.1/24
Port range: 61001-62000
(CPE2)
IPv4 address: 120.10.10.1/24
Port range: 62001-63000

Here, when a data packet is transmitted from the user A to the user B, first, a data packet in which the destination address is “120.10.10.1/24” which is the IPv4 address of the CPE2 and the destination port number is “62100”. It is transmitted from the terminal of user A to CPE1. Here, in the conventional IP packet transfer technique, a packet is transferred based only on the destination IP address. For this reason, the CPE 1 that has received the data packet determines that the data packet is a packet addressed to the local station because the destination IP address is the same as the IP address of the local station, and receives the local packet. Thereafter, the CPE 1 refers to the destination port number of the packet received by the local station, and passes the packet to the software waiting at the corresponding port number. However, in CPE1, since there is no software waiting on the corresponding port number “62100”, the data packet is discarded. As described above, in the A + P environment, the packet to be transferred to the CPE 2 is also received and discarded by the CPE 1, so that the packet cannot be transferred appropriately. Non-Patent Documents 1, 2, and 3 describe sharing an IPv4 address among a plurality of CPEs, but what about the above-mentioned problem related to packet transfer between CPEs assigned the same IPv4 address? Not listed.

Therefore, the present invention has been made in view of the above circumstances, and provides a packet transfer apparatus, a transfer method, and a program capable of appropriately transferring packets between CPEs having the same IP address. For the purpose.

In order to solve the above-described problem, according to the present invention, a packet transfer device to which an IP address common to another device on the network and a different port range are assigned, a packet receiving unit that receives a data packet, and a packet Based on the destination IP address and destination port number of the data packet received by the receiving unit, the packet identifying unit for determining whether the received data packet is addressed to the own station, and the packet identifying unit And a packet transfer unit that transfers the data packet when it is determined that the packet is not addressed to the own station.

In this way, by determining whether the data packet is addressed to the own station based on the destination port number as well as the destination IP address of the received data packet, another packet to which the same IP address is assigned is determined. Even when a data packet destined for the device is received, it can be appropriately transferred without being erroneously received by the own station.

Further, the packet identification unit (1) when the destination IP address of the received data packet is the same as the IP address of the local station, and the destination port number of the received data packet is not included in the port range of the local station, Or (2) When the destination IP address of the received data packet is different from the IP address of the own station, it is determined that the received data packet is not addressed to the own station, and (3) the destination IP address of the received data packet is If the destination port number of the received data packet is included in the port range of the local station, it may be determined that the received data packet is addressed to the local station.

The packet transfer unit may specify an identifier from the destination IP address and destination port number of the received data packet, and may transfer the data packet based on the specified identifier. The identifier is, for example, an IPv6 address or a layer 2 address, and the packet transfer unit may be configured to transfer the data packet by encapsulating or converting the protocol using the IPv6 address or the layer 2 address. .

Further, the packet transfer unit, when the packet identification unit determines that the received data packet is not addressed to the local station because the destination IP address of the received data packet is different from the IP address of the local station. On the basis of this, a configuration including a routing unit that performs routing of the data packet may be employed. The packet transfer unit may be configured to transfer the data packet based on the route selected by the routing unit.

The packet transfer apparatus may further include an extended route table in which information on the destination IP address, the port range, and the transfer destination is associated. In this case, the packet identification unit determines whether or not the received packet is addressed to the own station based on the extended route table, and the packet transfer unit determines whether the packet is based on the information about the transfer destination in the extended route table. It may be a thing to transfer.

Furthermore, according to the present invention, there is provided a packet transfer method in a packet transfer apparatus to which an IP address common to another apparatus on the network and a different port range are assigned, the step of receiving the data packet, Based on the destination IP address and the destination port number, a step of determining whether or not the received data packet is addressed to the own station, and if it is determined that the data packet is not addressed to the own station, the data packet is transferred A packet transfer method comprising: a packet transfer unit; and a program for causing a packet transfer apparatus to execute the packet transfer method.

Therefore, according to the present invention, even when sharing the same IP address with other devices, it is properly determined whether or not the received data packet is addressed to the own station. It is possible to provide a packet transfer apparatus, a packet transfer method, and a program capable of transferring the data packet to a device as a proper destination.

It is the figure which showed the outline of the network structure of the packet transfer system in embodiment of this invention. It is a figure which shows schematic structure of CPE in the 1st Embodiment of this invention. It is a flowchart which shows the flow of the packet transfer process in embodiment of this invention. It is a figure which shows schematic structure of CPE in the 2nd Embodiment of this invention. It is a figure which shows an example of the extended path | route table in the 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing an outline of a network configuration in a packet transfer system including a packet transfer apparatus of the present invention. As shown in FIG. 1, the packet transfer system according to the present embodiment includes

terminals

10 and 30, which are PCs in a user's home, and a CPE (Customer Premise) for connecting these

terminals

10 and 30 to a first network 100. Equipment) 20 and 40 and a relay router 50 for connecting the first network 100 and the second network 200.

In the present embodiment, the first network 100 is a network of a service provider that provides an Internet connection service, and the second network 200 is a public network such as the Internet. The

terminals

10 and 30 are IPv4 compatible terminals, and can use IPv4 content provided by the server 60 on the second network 200. The

CPEs

20 and 40 are service subscriber routers installed in the subscriber premises of services provided from service providers of the first network 100.

In the first network 100 in the present embodiment, the same IPv4 address and different port ranges are assigned to the

CPEs

20 and 40 from the service provider using A + P as follows.
(CPE20)
IPv4 address: 120.10.10.1/24
Port range: 2000-2999
(CPE40)
IPv4 address: 120.10.10.1/24
Port range: 3000-3999
Note that a common IPv4 address need not be assigned to all CPEs in the first network 100, and a plurality of IPv4 addresses may be shared by a plurality of CPEs.

Subsequently, the packet transfer process in the first embodiment of the present invention will be described with reference to FIG. 2 and FIG. First, FIG. 2 is a block diagram showing a schematic configuration of the CPE 20 in the present embodiment. As shown in FIG. 2, the CPE 20 includes a packet receiving unit 201 that receives a data packet from the terminal 10 and the like, a packet identifying unit 202 that determines whether the received packet is addressed to the local station, and the CPE 20 Packets are transferred from the application 203 composed of various applications executed in the above, the packet routing unit 204 for routing the received data packet based on the routing table 205, and the tunnel interface 2061 and the Ethernet (registered trademark) interface 2062. A packet transfer unit 206 is provided. 2 is executed by a CPU (not shown) provided in the CPE 20 by calling a program stored in a memory (not shown) such as a ROM provided in the CPE 20. Alternatively, all or part of the processing of each unit may be implemented as ASIC (Application Specific Specific Integrated Circuit) in each device, and the configuration may be realized by hardware by the ASIC. Further, the CPE 40 has the same configuration as the CPE 20.

FIG. 3 is a flowchart showing a flow of packet transfer processing in the CPE 20. In this process, first, the packet receiving unit 201 receives a data packet from the terminal 10 and sends it to the packet identifying unit 202 (S1). The packet identification unit 202 determines whether or not the destination IPv4 address of the received data packet is the same as the IPv4 address of the local station (CPE 20) (S2).

Here, if the destination IPv4 address of the data packet is the same as the IPv4 address of the own station (S2: Yes), then whether or not the destination port number of the data packet is included in the port range assigned to the own station. Is determined (S3). When the destination port number is included in the port range assigned to the own station (S3: Yes), the received data packet is determined to be a packet addressed to the own station, and is received by the own station ( S4). Specifically, when it is determined that the received data packet is addressed to the own station, the data packet is sent to the application 203 corresponding to the destination port number, and the corresponding processing is executed.

On the other hand, when the destination port number is not included in the port range assigned to the own station (S3: No), the packet identification unit 202 determines that the received packet is not a packet addressed to the own station, and the data The packet is sent to the packet transfer unit 206. The packet transfer unit 206 transfers the received data packet. Here, a plurality of CPEs to which the same IPv4 address is assigned by A + P exist in the first network 100. For this reason, when a data packet is transferred based only on the destination IPv4 address as in the prior art, the CPE as the transfer destination cannot be uniquely specified, and the data packet is transferred to a CPE different from the destination. There is also a possibility that the data packet returns to the local station to which the same IPv4 address is assigned.

Therefore, in A + P, in addition to the commonly assigned IPv4 address, an identifier for identifying each CPE for transfer within the first network 100 is set for each CPE on the first network 100. Is done. In this embodiment, the service provider assigns different IPv6 addresses to the

CPEs

20 and 40 in addition to the common IPv4 address. Specifically, the IPv6 address “2100: 10: 10 :: / 48” is assigned to the CPE 20, and the IPv6 address “2100: 10: 1 :: / 48” is assigned to the CPE 40. Then, in the packet transfer unit 206, the tunnel interface 2061 uses the technology called SAM (Stateless Address Mapping, Non-Patent Document 1) from the destination IPv4 address and the destination port number of the received data packet to determine the destination CPE. Find the IPv6 address. Then, the data packet is encapsulated at the IPv6 address obtained by the SAM, and transferred in the first network 100. As an identifier for identifying each CPE, a layer 2 address can be used in addition to the IPv6 address. In this case, the data packet is encapsulated with a layer 2 address and transferred within the first network 100.

In the packet transfer process of the present embodiment, the packet identification unit 202 has the same destination IPv4 address as the IPv4 address of the local station (S2: Yes), but the port to which the destination port number is assigned to the local station. When it is determined that it is not within the range (S3: No), the data packet is sent to the tunnel interface 2061 of the packet transfer unit 206. As a result, as described above, the tunnel interface 2061 obtains an IPv6 address from the destination IPv4 address and the destination port number of the received data packet, and the data packet is encapsulated with this IPv6 address and transferred (S6).

On the other hand, when the destination IPv4 address is different from the IPv4 address of the local station (S2: No), the packet identifying unit 202 determines that the received data packet is not a packet addressed to the local station, and the packet routing unit 204 Send to. In this case, a conventional transfer process is performed by a normal packet transfer technique. Specifically, the packet routing unit 204 refers to the route table 205 and selects a corresponding route by a longest match from the destination IPv4 address (S5). Then, the data packet is sent to the packet transfer unit 206, and the packet transfer unit 206 performs transfer based on the selected route (S6).

Specifically, when the output interface of the selected route is the tunnel interface 2061 in the packet routing unit 204, the data packet is sent to the tunnel interface 2061 of the packet transfer unit 206. In the tunnel interface 2061, as in the case described above, an IPv6 address is obtained by the SAM, and the data packet is encapsulated by the IPv6 address and transferred. On the other hand, if the output interface of the route selected by the packet routing unit 204 is not the tunnel interface 2061, for example, the Ethernet interface 2062, the data packet is sent to the Ethernet interface 2062 of the packet transfer unit 206. The Ethernet interface 2062 is an IPv4 transferable interface, and the data packet is transferred as an IPv4 packet without being encapsulated by the IPv6 address. *

Since the output interface (next hop) corresponding to the destination IPv4 address is registered in the route table 205, if the IPv4 address of the received data packet is the same as the IPv4 address of the local station, the route is stored. There is no point in referring to Table 205. Therefore, in the packet identification unit 202 as described above, when the destination IPv4 address is the same as that of the own station (S2: Yes) and the destination port number is not included in the port range of the own station (S3: No) The data packet is sent directly to the packet transfer unit 206 without passing through the packet routing unit 204.

According to the packet transfer process as described above, communication between the terminal 10 and the terminal 30 indicated by the solid line in FIG. 1 can be appropriately performed. Specifically, first, a data packet having the destination address as the IPv4 address “120.10.10.1/24” of the CPE 40 and the destination port number “3010” is transmitted from the terminal 10 to the terminal 30 to the CPE 20 (S1). . In the CPE 20, the packet identification unit 202 first determines that the destination IPv4 address “120.10.10.1/24” of the received data packet is the same as the IPv4 address “120.10.10.1/24” of the own station ( S2: Yes). Subsequently, since the destination port number “3010” is not included in the port range “2000-2999” of the local station (S3: No), it is determined that the destination port number is not addressed to the local station, and the data packet is transferred to the tunnel of the packet transfer unit 206. Send to interface 2061. In the tunnel interface 2061, the IPv6 address “2100: 10: 1 :: / 48” of the CPE 40 is obtained by the SAM, and the data packet is encapsulated with the obtained IPv6 address. The encapsulated data packet is transferred in the first network 100 based on the IPv6 address (S6) and received by the CPE 40. Thereafter, the encapsulation is released by the CPE 40 and the data packet is sent to the terminal 30.

As described above, in this embodiment, when the destination IPv4 address of the received data packet is the same as the IPv4 address assigned to the local station, the data addressed to the local station based on the destination port number in the CPE 20. Determine whether it is a packet. Therefore, even when a data packet destined for another CPE to which the same IPv4 address is assigned is received, it can be appropriately transferred without receiving it. Further, in the above embodiment, since the data packet is transferred in the first network 100 as in the conventional case by the IPv6 address, there is no need to change the existing router in the first network 100, and the existing network Can be used.

In this embodiment, for example, as indicated by a broken line in FIG. 1, even when a data packet is transmitted to the terminal 30 from the server 60 on the second network 200, appropriate packet transfer is possible. It is. Specifically, first, a data packet with the destination address set to the IPv4 address “120.10.10.1/24” of the CPE 40 and the destination port number “3010” is transmitted from the server 60, and the relay router 50 sends the data packet. Received. The relay router 50 is an A + P-compatible router. In order to deliver the received data packet to the CPE 40, the CPE 40 is transmitted by the SAM from the destination IPv4 address “120.10.10.1/24” and the destination port number “3010” of the received data packet. IPv6 address “2100: 10: 1 :: / 48” is obtained.

Then, the data packet is encapsulated by the obtained IPv6 address and transferred within the first network 100. At this time, since the IPv6 address obtained by the SAM is unique to the CPE 40, the destination of the data packet is uniquely specified. However, when an incorrect IPv6 address, for example, the IPv6 address “2100: 10: 10 :: / 48” of the CPE 20 is added to the data packet as the IPv6 address of the CPE 40 due to some setting mistake or the like, the data The packet is transferred in the first network 100 based on the IPv6 address of the CPE 20 and reaches the CPE 20 instead of the CPE 40.

In the CPE 20 in the above embodiment, even when a data packet is erroneously transmitted in this way, it can be transferred to the CPE 40 which is a valid recipient. Specifically, first, the data packet erroneously encapsulated with the IPv6 address of the CPE 20 is received by the packet receiving unit 201 of the CPE 20, and the encapsulation is released. Then, the decapsulated data packet is sent to the packet identification unit 202. Based on the destination IPv4 address “120.10.10.1/24” and the destination port number “3010” of the data packet, the packet identification unit 202 determines whether or not the received data packet is addressed to the own station.

Here, the packet identification unit 202 receives the received data packet because the destination IPv4 address of the received data packet is the same as the IPv4 address of the local station, but the destination port number is not included in the port range of the local station. It is determined that the packet is not addressed to the local station. Then, the data packet is sent to the tunnel interface 2061 of the packet transfer unit 206. In the tunnel interface 2061, the IPv6 address of the CPE 40 is obtained from the destination IPv4 address and the destination port number of the received data packet, and the data packet is encapsulated with the obtained IPv6 address. Then, the encapsulated data packet is transferred again within the first network 100 and delivered to the CPE 40.

In this way, even when routing is performed based on the IPv6 address individually assigned to each CPE, the CPE 20 checks whether it is addressed to the own station based on the destination IPv4 address and the destination port number. By doing so, it is possible to transfer a data packet transmitted in error to a correct destination.

Furthermore, by configuring as in the present embodiment, the service provider can appropriately grasp and manage the presence / absence of a failure of the CPE 20 and CPE 40 in the first network 100. Specifically, for example, when a ping command is transmitted from the relay router 50 to confirm the failure of the CPE 40, when the ping is erroneously delivered to the CPE 20, conventionally, the CPE 20 is only sent to the destination IPv4 address. Based on this, ping was received by itself and a response message was returned to the relay router 50. Based on this reply, the relay router 50 has erroneously determined that the CPE 40 is appropriately communicating. On the other hand, in the

CPEs

20 and 40 of the present embodiment, it is determined whether or not the ping delivered to the local station is addressed to the local station based on the destination IPv4 address and the destination port number. Is configured to perform transfer. As a result, it is possible to prevent a local station from receiving and responding to a ping command to be responded by another CPE.

Note that ping does not have a TCP / UDP header, so there is no port number. Therefore, in this embodiment, when the ping is transmitted from the relay router 50, the IPv6 address by the SAM is obtained by using the ICMPID included in the ICMP header of the ping instead of the destination port number. When the ping encapsulated with the obtained IPv6 address is received by the CPE 20, the packet identification unit 202 of the CPE 20 refers to the ICMP ID of the ping instead of the destination port number, and is included in the port range of the local station. It is determined whether or not the local station is received depending on whether or not it is received. In addition, it is also possible to send a ping to a port reserved for management of each CPE by using UDP-ping and check the status based on the reply.

Next, with reference to FIG. 4, the packet transfer process in the CPE 20a in the second embodiment of the present invention will be described. As shown in FIG. 4, the present embodiment is different from the first embodiment in that a packet identification / routing unit 240 is provided instead of the packet identification unit 202 and the packet routing unit 204 in the first embodiment. . Furthermore, in the first embodiment, the routing is made with reference to the general routing table 205 using only the destination IP address as a key. However, in this embodiment, the route is expanded by adding a new port range. The table 250 is used to perform routing using the destination IP address and port range as keys. The other processing units are the same as in the first embodiment, and the processing of each unit of the CPE 20a shown in FIG. 4 is also executed by the CPU by calling a program stored in the ROM. Alternatively, all or part of the processing of each unit may be mounted on each device as an ASIC, and a configuration realized by hardware by the ASIC may be employed.

Next, the flow of packet transfer processing in the CPE 20a of this embodiment will be described. In the present embodiment, when the packet reception unit 201 of the CPE 20a receives a data packet from the terminal 10 or the like, the data packet is sent to the packet identification / routing unit 240. Then, the packet identification / routing unit 240 refers to the extended route table 250 to determine whether or not the received data packet is addressed to the own station. FIG. 5 is a diagram showing an example of the extended route table 250 in the present embodiment. The extended route table 250 of this embodiment includes an item “port range” in addition to “destination address”, “next hop”, and “output interface” in the normal route table.

In this embodiment, a route is selected from the extended route table 250 based on the destination port number as well as the destination IPv4 address of the received data packet. Specifically, when the destination IPv4 address of the received data packet is “120.10.10.1/24” and the destination port number is “2010”, the packet identification / routing unit 240 selects the route R1 from the extended route table 250. To do. Since the output interface of the selected route R1 is a local interface, it is determined that the received data packet is addressed to the own station. The received data packet is sent from the local interface to the application 203 and received by the local station.

Further, when the destination IPv4 address of the received data packet is “120.10.10.1/24” and the destination port number is “3010”, the route R2 is selected from the extended route table 250. In this case, since the output interface in the selected route R2 is the tunnel interface 2061, it is determined that the received data packet is not addressed to the own station. Then, the data packet is sent to the tunnel interface 2061, and the tunnel interface 2061 obtains an IPv6 address based on the destination IPv4 address and the destination port number, and the data packet is encapsulated by the obtained IPv6 address and transferred. .

Furthermore, when the destination IPv4 address of the received data packet is “120.1.1.0/24” and the destination port number is “10110”, the route R30 is selected from the extended route table 250. Since the output interface of the selected route R30 is the Ethernet interface 2062, it is determined that the received data packet is not addressed to the own station. Then, the data packet is sent to the Ethernet interface 2062 and transferred without being encapsulated.

As described above, in the present embodiment, whether or not the received data packet is addressed to the own station is determined by performing routing using the extended routing table 250 based on both the destination IPv4 address and the destination port number. It becomes possible to judge. Thereby, also in this embodiment, similarly to the first embodiment, it is possible to appropriately perform communication between terminals to which the same IPv4 address is assigned.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments and can be modified in various ranges. For example, in the first embodiment, a data packet received by the packet receiving unit 201 is first sent to the packet identifying unit 202, and the packet identifying unit 202 determines whether the packet is addressed to the own station. Although configured, the present invention is not limited to this. For example, when a data packet is received by the packet receiving unit 201, first, a configuration may be used in which the packet is sent to the packet routing unit 204. Then, the packet routing unit 204 refers to the route table 205 and tentatively determines whether the received data packet is addressed to the own station based on only the destination IP address, and then determines that the received data packet is addressed to the own station. In this case, the packet identification unit 202 may further determine whether or not the destination port number of the data packet is included in the port range of the own station.

In this case, a local interface is registered as an output interface in a route corresponding to the IPv4 address of the local station with reference to the route table 205. Then, a route is selected with reference to the route table 205 for the received data packet, and if the output interface of the selected route is a local interface, a temporary determination is made that it is addressed to the own station. . Then, if a temporary determination is made that it is addressed to the own station, the packet identification unit 202 determines whether or not the destination port number is included in the port range of the own station. The received data packet is finally determined to be addressed to the own station. On the other hand, although the packet routing unit 204 tentatively determines that it is addressed to the own station with reference to the route table 205, the packet identification unit 202 does not include the destination port number in the port range of the own station. If it is determined that the received data packet is not addressed to the own station, it is finally determined and transfer processing is performed. Even in the case of such a configuration, the same effect as in the case of the first embodiment can be obtained.

In the above case, the IPv4 address set for the local interface is not only the local address IPv4 address but also the well-known address 192.0.0.0/29 by DS-Lite (Non-Patent Document 4), etc. It is also possible to set to.

In the above embodiment, in the tunnel interface 2061 of the packet transfer unit 206, when the destination IPv4 address of the received data packet is an address corresponding to the SAM, the IPv6 address is determined from the destination IPv4 address and the port number of the data packet. If the destination IPv4 address of the received data packet is not an address corresponding to the SAM, the IPv6 address of the relay router 50 may be encapsulated as the destination address. In this case, whether the destination IPv4 address of the data packet corresponds to SAM is determined by the prefix of the IPv4 address.

Further, in the above embodiment, the tunnel interface 2061 is configured to obtain an IPv6 address using SAM. However, the present invention is not limited to this, and is described in Non-Patent Document 2 and Non-Patent Document 3, for example. The IPv6 address may be obtained by another A + P method.

In the above embodiment, the tunnel interface 2061 encapsulates the IPv4 data packet with the IPv6 address and then transfers the packet within the first network 100, which is an IPv6 network. However, the present invention is not limited to this. Is not to be done. For example, in another embodiment, the packet transfer unit 206 may include a protocol conversion interface instead of or in addition to the tunnel interface 2061. Then, the protocol conversion interface converts the IPv4 header of the received data packet into an IPv6 header including an IPv6 address obtained by SAM or the like, thereby performing protocol conversion from IPv4 to IPv6. It is also possible to transfer inside.

10, 30

Terminal

20, 40 CPE
50 relay router 60 server 100 first network 200 second network 201 packet receiving unit 202 packet identifying unit 203 application 204 packet routing unit 205 route table 206 packet forwarding unit 2061 tunnel interface 2062 Ethernet interface 240 packet identification / routing unit 250 extension Route table

Claims

A packet forwarding device to which an IP address common to another device on the network and a different port range are assigned,
A packet receiver for receiving data packets;
A packet identifying unit for determining whether the received data packet is addressed to the own station based on a destination IP address and a destination port number of the data packet received by the packet receiving unit;
A packet transfer apparatus comprising: a packet transfer unit that transfers the data packet when the packet identification unit determines that the data packet is not addressed to the own station.
The packet identification unit
(1) The destination IP address of the received data packet is the same as the IP address of the local station, and the destination port number of the received data packet is not included in the port range of the local station, or (2) the reception If the destination IP address of the received data packet is different from the IP address of the local station, it is determined that the received data packet is not addressed to the local station;
(3) The received data packet when the destination IP address of the received data packet is the same as the IP address of the local station and the destination port number of the received data packet is included in the port range of the local station 2. The packet transfer apparatus according to claim 1, wherein the packet transfer apparatus determines that the address is addressed to the own station.
The packet transfer unit specifies an identifier from a destination IP address and a destination port number of the received data packet, and transfers the data packet based on the specified identifier. The packet transfer apparatus described in 1.
The identifier is an IPv6 address or a layer 2 address,
The packet transfer apparatus according to claim 3, wherein the packet transfer unit transfers the data packet by encapsulating or converting the protocol using the IPv6 address or the layer 2 address.
The packet transfer unit, when the packet identification unit determines that the received data packet is not addressed to the local station because the destination IP address of the received data packet is different from the IP address of the local station. A routing unit for routing the data packet based on
5. The packet transfer device according to claim 1, wherein the packet transfer unit transfers the data packet based on a route selected by the routing unit. 6.
The packet transfer apparatus further includes an extended route table in which information on a destination IP address, a port range, and a transfer destination is associated,
The packet identification unit determines whether the received packet is addressed to the own station based on the extended route table,
5. The packet transfer apparatus according to claim 1, wherein the packet transfer unit transfers the packet based on information related to a transfer destination in the extended route table. 6.
A packet transfer method in a packet transfer apparatus to which an IP address common to another apparatus on the network and a different port range are assigned,
Receiving a data packet;
Determining whether the received data packet is addressed to its own station based on a destination IP address and a destination port number of the received data packet;
A packet transfer method comprising: a packet transfer unit that transfers the data packet when it is determined that the data packet is not addressed to the own station.
A program for causing a packet transfer apparatus to execute the packet transfer method according to claim 7.